JP2013086461A - Recording medium for aqueous inkjet ink, aqueous ink-jet printed matter, and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based ink-jet ink having good adhesion to a water-based ink without causing a surface treatment or a drawing process essential when using a conventional plastic film as a base material, and causing no problems such as peeling after ink-jet printing. Provide recording media and printed materials.
A layer (A2) surface of a multilayer film in which a layer (A1) containing a polyolefin resin (A1) as a main component and a layer (A2) containing an acid-modified olefin resin (A2) are laminated. And at least a colorant, a resin having a polar group, and water or a water-soluble organic solvent, having a surface tension at 25 ° C. in the range of 15 mN / m to 30 mN / m and a viscosity of 5 mPa · A method for producing a water-based inkjet printed matter, wherein printing is performed by an ink-jet recording method using a water-based ink that is less than or equal to s, and a printed matter obtained thereby.
[Selection figure] None

Description

  The present invention relates to a water-based inkjet recording medium that enables inkjet printing even on a plastic substrate. Specifically, the adhesion between the water-based inkjet ink and the plastic substrate is excellent, and the printed surface is peeled off after printing. The present invention relates to a recording medium for water-based ink-jet ink having no ink and a printed matter thereof.

  In recent years, with the progress of multimedia technology, ink jet printers have become widespread regardless of business use and consumer use. Inkjet printers have many features such as being easy to make multicolor images and large images, printing on uneven surfaces as well as smooth surfaces, and enabling on-demand printing. Have. In particular, inkjet printing using water-based ink, which is less likely to cause problems in terms of environment and safety than oil-based ink, has become the mainstream recently.

  The ink-jet recording material using paper as a support has a problem that the appearance is deteriorated due to occurrence of a phenomenon called cockling in which the support is waved when touched with water or tearing. In order to solve such a problem, it has been proposed to use an ink jet recording medium having a plastic film itself as a support and an ink receiving layer thereon, and to perform printing (for example, Patent Document 1). ~ 4). Such a medium is excellent in water resistance and can be used as an outdoor advertisement, a poster, a label, wallpaper, or the like. However, the surface of the plastic film has poor adhesion to the ink-jet ink, and a layer usually called an anchor layer, primer layer, undercoat layer, adhesive layer, etc. is formed on the film surface, and polyurethane, polyacryl, etc. The step of providing an ink receiving layer containing as a main component was essential. Such a surface treatment process not only leads to an increase in cost, but also requires a lot of time for production because the number of processes increases. Furthermore, when the surface treatment is performed by application of a paint containing a solvent, a step for removing the contained solvent is required, and when the solvent is an organic solvent, the burden on the environment is increased. On the other hand, there has also been reported an ink jet recording medium in which micropores are provided on the film surface instead of applying an ink receiving agent, and the micropores are fixed by absorbing ink (see, for example, Patent Document 5). However, since the stretching process is necessary and the micropores diffusely reflect light, the use is usually limited depending on the field where the film is white and transparency is required.

Japanese Patent Laid-Open No. 10-119428 JP 2001-150612 A Japanese Patent Laid-Open No. 2002-103802 JP 2007-130780 A JP 2001-181424 A

  The object of the present invention has been made in view of the above problems, and has good adhesion to water-based ink without performing a surface treatment or stretching process essential when using a conventional plastic film as a substrate. Another object of the present invention is to provide a recording medium for an aqueous ink-jet ink which does not cause problems such as peeling after ink-jet printing, and a printed matter thereof.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have found that a layer (A1) containing a polyolefin resin (a1) as a main component and a layer (A2) containing an acid-modified olefin resin (a2). The present invention has been completed by finding that the above-mentioned problems can be solved by using a multilayer film formed by laminating and as a recording medium for an aqueous inkjet ink.

  That is, in the present invention, the layer (A1) containing the polyolefin resin (a1) as a main component and the layer (A2) containing the acid-modified olefin resin (a2) are in the order of (A1) / (A2). A recording medium for water-based ink-jet inks characterized by being laminated, a printed matter obtained by performing ink-jet printing using water-based ink on the layer (A2) of the recording medium, and a method for producing them It is to provide.

  The water-based inkjet printed matter obtained by the present invention can be easily obtained by directly performing inkjet printing on a multilayer film. The design can be easily changed by selecting the layer structure of the multilayer film according to the target performance (transparency, rigidity, workability, etc.) and application (packaging material, poster, label, etc.). Excellent. The printed matter obtained has good adhesion between the water-based ink and the multilayer film, so that even if it is stored for a long period of time, the printed part will not peel off. It is also possible to form a bag.

  The plastic film functioning as a support for the aqueous inkjet printed material of the present invention comprises at least a layer (A1) containing a polyolefin resin (a1) as a main component and a layer (A2) containing an acid-modified olefin resin (a2). It is what you have. This layer (A2) has a function as an easily adhesive layer with water-based ink as well as a function as a support. In the present invention, “main component” means that the specific resin is contained in an amount of 80% by mass or more based on the total amount of the resin composition forming the layer, and preferably 85% by mass. The above is a specific resin. Further, in the present invention, “containing” means that the specific resin is contained in an amount of 1% by mass or more with respect to the total amount of the resin composition forming the layer, and preferably 20% by mass or more. Say that it is a specific resin.

  The opposite side of the printing surface of the water-based inkjet printed matter of the present invention is a layer (A1) containing a polyolefin resin (a1) as a main component. Examples of the polyolefin-based resin (a1) that can be used here include homopolymers or copolymers of α-olefins having 2 to 6 carbon atoms. The copolymerization type may be a block copolymer or a random copolymer. Further, as the polyolefin-based resin (a1), it is preferable to use a resin having a melting point of 110 ° C. or more from the viewpoint of maintaining the appearance during molding after recording and suppressing the warpage of the film itself.

  As the polyolefin resin (a1), for example, any of those known as polypropylene resin, polyethylene resin and the like can be used. For example, as a polypropylene resin, a propylene homopolymer, a propylene-ethylene copolymer, a propylene-butene-1 copolymer, a propylene-ethylene-butene-1 copolymer, an ethylene-propylene block copolymer, a metallocene catalyst And polypropylene. These may be used alone or in combination of two or more. When the water-based inkjet ink recording medium before inkjet printing is rolled up and stored for a long period of time, it is preferable to use a crystalline propylene-based resin from the viewpoint of preventing blocking. In addition, in this application, crystallinity means having a peak of 0.5 J / g or more in the range of 95-250 degreeC in DSC (differential scanning calorimetry).

The polypropylene resin has a melt flow rate (hereinafter referred to as “230 ° C. MFR”; a value measured at 230 ° C. and 21.18 N in accordance with JIS K7210: 1999) of 0.5 to 30. Those having a melting point of 120 to 165 ° C. at 0.0 g / 10 min are preferred, and more preferably those having an MFR of 230 ° C. of 2.0 to 15.0 g / 10 min and a melting point of 125 to 162 ° C. . If the MFR and the melting point are in this range, the film shrinkage is small even when the printed matter is subjected to thermoforming, etc., so that the appearance of the printed surface can be maintained and the warp of the medium itself is not generated, and the coextrusion multilayer The film-forming property when it is used as a film is also improved. It is preferable that density is 0.890~0.910g / cm ^3, more preferably 0.895~0.905g / cm ^3.

  In particular, when a propylene-ethylene block copolymer is used for the layer (A1), the surface is modified into a satin finish, and the generation of wrinkles when winding the multilayer film into a roll can be suppressed. Blocking when stored in roll form can be reduced. Here, the propylene-ethylene block copolymer is a resin obtained by block polymerization of propylene and ethylene. For example, propylene obtained by polymerizing ethylene or ethylene and propylene in the presence of a propylene homopolymer. -An ethylene block copolymer etc. are mentioned.

  Further, when a mixed resin of crystalline propylene resin and ethylene / propylene rubber (hereinafter referred to as “EPR”) is used for the layer (A1), the surface of the layer (A1) can be easily modified into a satin finish. Can do. As the crystalline propylene-based resin used at this time, a highly versatile propylene homopolymer is preferable. On the other hand, as the EPR used at this time, those having a weight average molecular weight in the range of 400,000 to 1,000,000 are preferable in that irregularities are formed on the film surface and the surface can be modified into a satin finish, A range is more preferable. In addition, the EPR content in the mixed resin is preferably in the range of 5 to 35% by mass in that the film surface can be uniformly modified into a satin finish. The MFR (230 ° C.) of the mixed resin of the crystalline propylene polymer and EPR is preferably in the range of 0.5 to 15 g / 10 minutes from the viewpoint of easy extrusion. In addition, the weight average molecular weight of the EPR was obtained by calculating a component extracted from the mixed resin by a cross fractionation method at 40 ° C. using orthodichlorobenzene as a solvent by GPC (gel permeation chromatography). It is. The content of EPR in the mixed resin is obtained from the amount of EPR extracted by cross-fractionation at 40 ° C. using orthodichlorobenzene as a solvent.

  The method for producing the mixed resin of the crystalline propylene-based resin and EPR is not particularly limited. As a specific example, for example, a propylene homopolymer and ethylene / propylene rubber are separately mixed using a Ziegler type catalyst. After producing by a combination method, a slurry polymerization method, a gas phase polymerization method, etc., a propylene homopolymer is produced in the first stage by a method of mixing both with a mixer or a two-stage polymerization method, and then the second stage. And a method of generating EPR in the presence of this polymer.

  The Ziegler-type catalyst is a so-called Ziegler-Natta catalyst, and is obtained by supporting a transition metal compound such as a titanium-containing compound or a transition metal compound on a support such as a magnesium compound. The combination with the promoter of an organometallic compound is mentioned.

Examples of the polyethylene resin include medium density polyethylene (MDPE) and high density polyethylene (HDPE), and the density is preferably 0.92 to 0.97 g / cm ³ . When the density is within this range, the film has an appropriate rigidity and improves film formability and extrusion suitability. Moreover, it is preferable that it is 2-20 g / 10min, and, as for MFR (190 degreeC, 21.18N) of a polyethylene-type resin, it is more preferable that it is 3-10 g / 10min. When the MFR is within this range, the extrudability of the film is improved, the generation of wrinkles that are likely to occur when the multilayer film is rolled up can be suppressed, and the roll-out property from the roll is excellent. Furthermore, these polyethylene resins preferably have a melting point of 110 to 135 ° C, more preferably a melting point of 115 to 130 ° C. When the melting point is within this range, the film shrinks little even when heated by molding after printing, etc., so that the appearance of the recording surface can be maintained, and warping of the film itself can be suppressed. These may be used alone or in combination of two or more.

  As a layer (A1) which has polyolefin resin (a1) as a main component, it may be a single layer or may have a multilayer structure of two or more layers. From the viewpoint of more excellent rigidity and heat resistance and excellent workability when the printed material is secondarily processed, a film having a single layer or a multilayer structure mainly composed of a polypropylene resin is preferable. For example, when a printed material is used as a package, the outermost layer on the surface opposite to the printed surface is 1-butene having 1-butene and propylene as essential components as described in JP-A-2006-213065. By using a heat seal layer containing a copolymer and a copolymer containing propylene and ethylene as essential components, an easily openable bag can be obtained. Similarly, when used as a lid, it can be easily opened by adopting a multilayer structure as described in JP-A-2004-75181 and JP-A-2008-80543. It is. Furthermore, when a cyclic polyolefin resin as described in JP 2010-234660 A is used as one layer in a multilayer structure, it is possible to obtain a printed material having easy tearability, depending on the use of the printed material. It is preferable to employ various multilayer configurations.

  Moreover, it can also be set as the inkjet printed material (label) which can be affixed on a signboard, a vehicle, etc. by providing an adhesive layer on a layer (A1) [surface opposite to layer (A2) mentioned later]. The type of the adhesive is not particularly limited. For example, natural rubber, synthetic rubber, acrylic, urethane, vinyl ether, silicone, amide and styrene adhesive, styrene elastomer, olefin elastomer Etc. For the purpose of controlling the adhesive properties, etc., the pressure-sensitive adhesive layer may include, for example, terpene resins such as α-pinene, β-pinene polymer, diterpene polymer, α-pinene / phenol copolymer, fat Appropriate tackifiers such as aromatic resins, aromatic resins, aliphatic / aromatic copolymer systems, other rosin resins, coumarone indene resins, (alkyl) phenol resins and xylene resins Can be blended. Among these, when laminating a layer (A1) and a layer (A2) to be described later by a coextrusion method, a method of simultaneously laminating an adhesive layer on the layer (A1) opposite to the layer (A2) by coextrusion Is preferable in the manufacturing cycle.

  The layer (A2) in the present invention is a layer containing the acid-modified olefin resin (a2) as an essential component. Although the olefin component which is the main component of the acid-modified polyolefin resin (a2) is not particularly limited, it has 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, 1-hexene and the like. Alkenes are preferred and mixtures of these may be used. Among these, alkene having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene is more preferable, ethylene and propylene are further preferable, and ethylene is most preferable. Moreover, the acid-modified polyolefin resin (a2) needs to contain a (meth) acrylic acid ester component. (Meth) acrylic acid ester components include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid Examples include octyl, decyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, and the like. From the viewpoint of easy availability and adhesiveness, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and hexyl acrylate are more preferable, and methyl acrylate and ethyl acrylate are more preferable. The (meth) acrylic acid ester component may be copolymerized with the olefin component, and the form thereof is not limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization. (Graft modification) and the like. (In addition, "(meth) acrylic acid ~" means "acrylic acid ~ or methacrylic acid ~".) Specifically, as an ethylene- (meth) acrylic acid ester copolymer, for example, Elvalloy ( Product name: Mitsui-DuPont Polychemical Co., Ltd.), Aklift (trade name: Sumitomo Chemical Co., Ltd.), etc. These may be used alone or in combination of two or more.

  Further, the acid-modified polyolefin resin (a2) may be acid-modified with an unsaturated carboxylic acid component. Examples of unsaturated carboxylic acid components include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, and the like, as well as unsaturated dicarboxylic acid half esters and half amides. It is done. Of these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable, and acrylic acid and maleic anhydride are particularly preferable. The unsaturated carboxylic acid component may be copolymerized with the olefin component, and the form thereof is not limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization (grafting). Modification). Specifically, examples of the ethylene-acrylic acid copolymer include Nucrel (trade name: Mitsui / DuPont Polychemical Co., Ltd.). Examples of the ethylene- (meth) acrylic acid ester-maleic anhydride copolymer include bondine (trade name: manufactured by Tokyo Materials Co., Ltd.). These may be used alone or in combination of two or more.

  Examples of the acid modification rate of the acid-modified olefin resin (a2) include adhesion to aqueous inkjet ink, suppression of blocking when winding and storing a multilayer film, suppression of appearance defects such as wrinkles after printing, etc. From the viewpoint of excellent balance, it is preferable to use 0.5 to 40%, more preferably 0.5 to 35%, and particularly preferably 0.5 to 30%.

  In the layer (A2) in the present invention, in addition to the acid-modified olefin resin (a2), other resins may be used in combination. In particular, it is preferable to use a polyolefin-based resin in combination because it is mixed with the acid-modified olefin-based resin (a2) and can be easily coextruded with the layer (A1). At this time, the acid-modified olefin resin (a2) is preferably contained in an amount of 20 parts by mass or more, particularly preferably 50 parts by mass or more in 100 parts by mass of the resin component forming the layer (A2).

  As the polyolefin resin, any of those exemplified for the polyolefin resin (a1) used for the layer (A1) can be suitably used. At this time, the polyolefin resin used in the layer (A1) and the layer (A2) may be the same or different. The polyolefin resin used in the layer (A2) may be a single resin or a mixture of plural kinds.

  In each of the layers (A1) and (A2), an antifogging agent, an antistatic agent, a thermal stabilizer, a nucleating agent, an antioxidant, a lubricant, an antiblocking agent, a release agent, and an ultraviolet absorber are added as necessary. Components such as a colorant and a colorant can be added within a range that does not impair the object of the present invention. In particular, the surface friction coefficient is preferably 1.5 or less, more preferably 1.0 or less in order to impart processing suitability when forming a film or packaging suitability when a printed material is used as a packaging material. It is preferable to add a lubricant, an antiblocking agent or an antistatic agent to the resin layer corresponding to the layer as appropriate.

  The total thickness of each of the layers (A1) and (A2) can be set as appropriate according to the use of the printed matter. For example, when the packaging material (bag or lid material) is used, the thickness is 20 to 50 μm. In the case of labels and posters, it is preferably in the range of 70 to 1000 μm. Further, the ratio of the thickness of the layer (A2) to the total thickness of the layers (A1) and (A2) is preferably in the range of 5 to 40% from the viewpoint of ensuring adhesion with the inkjet ink described later. The thickness of the layer (A2) is preferably in the range of 2 to 30 μm.

  The method for laminating the layer (A1) and the layer (A2) is preferably a coextrusion laminating method in which the layer (A1) and the layer (A2) are laminated adjacently. After laminating layers (A1) and (A2) in a molten state by various coextrusion methods such as coextrusion multi-layer die method, feed block method, etc., which are melt-extruded using an extruder of more than one table, inflation, T-die A method of processing into a long wound film by a method such as a chill roll method is preferable, and a coextrusion method using a T die is more preferable.

  Further, it is desirable that the surface of the layer (A2) is continuously subjected to surface treatment using corona discharge or plasma discharge under heating or in an inert gas atmosphere during the production of the multilayer film.

  The printed matter obtained by the present invention is obtained by inkjet printing using the aqueous ink on the multilayer film obtained above.

(Water-based ink)
The water-based ink used in the present invention comprises a coloring material, a resin having a polar group, and water or a water-soluble organic solvent, and has a surface tension at 25 ° C. in the range of 15 mN / m to 30 mN / m, The water-based ink has a viscosity of 5 mPa · s or less.

(Color material)
As the coloring material used in the water-based ink, a pigment or a dye is usually used, but it is preferable to use a pigment from the viewpoint of durability of printed matter. Examples of the dye include direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, soluble vat dyes, reactive disperse dyes, and various dyes that are usually used in inkjet recording. . In addition, as pigments, inorganic pigments such as barium sulfate, lead sulfate, titanium oxide, yellow lead, bengara, chromium oxide, carbon black, anthraquinone pigments, perylene pigments, disazo pigments, phthalocyanine pigments, isoindoline pigments And dioxazine pigments, quinacridone pigments, perinone pigments, and benzimidazolone pigments. These can be used alone or in combination. In general-purpose color printing, black ink, cyan ink, magenta ink, and yellow ink using black pigment, cyan pigment, magenta pigment, and yellow pigment are used.

  As the black pigment, it is preferable to use furnace black, lamp black, acetylene black, channel black and other carbon black, titanium black, etc. which have excellent light resistance and high hiding power.

  Furthermore, among the representative organic pigments of cyan, magenta, and yellow, which are the three primary colors, pigments that can be suitably used in the present invention are exemplified below.

  Examples of cyan pigments include C.I. I. Pigment Blue 1, C.I. I. Pigment Blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, and the like.

  Examples of magenta pigments include C.I. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 184, C.I. I. Pigment red 202, C.I. I. Pigment bio red 19, and the like.

  Examples of yellow pigments include C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, and the like.

  As for the particle diameter of the pigment, the primary particle diameter is preferably in the range of 1 to 500 nm, and more preferably in the range of 20 to 200 nm. The particle diameter of the pigment after being dispersed in the medium is preferably in the range of 10 to 300 nm, and more preferably in the range of 50 to 150 nm. The primary particle diameter of the pigment can be measured by an electron microscope, a gas or solute adsorption method, an air flow method, an X-ray small angle scattering method, and the like. The pigment particle diameter after dispersion can be measured by various methods, for example, centrifugal sedimentation method, laser diffraction method (light scattering method), ESA method, capillary method, electron microscope method and the like.

(Resin having a polar group)
Resins having polar groups used in the present invention include, for example, proteins such as glue, gelatin, casein and albumin; natural rubbers such as gum arabic and tragacanth; glucosides such as saponin; alginic acid and propylene glycol alginate ester, alginic acid Alginic acid derivatives such as triethanolamine and ammonium alginate; natural polymers such as cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, and ethylhydroxyethylcellulose; polyvinyl alcohols; polyvinylpyrrolidones; polyacrylic acid and acrylic acid-acrylonitrile Polymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic ester copolymer, acrylic acid-acrylic Acrylic resin such as alkyl ester copolymer; styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer Styrene-acrylic acid resin such as styrene-α-methylstyrene-acrylic acid-acrylic acid alkyl ester copolymer; styrene-maleic acid; styrene-maleic anhydride; vinylnaphthalene-acrylic acid copolymer; vinylnaphthalene- Maleic acid copolymer: Acetic acid such as vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl ethylene copolymer, vinyl acetate maleate ester copolymer, vinyl acetate crotonic acid copolymer, vinyl acetate acrylic acid copolymer, etc. Synthetic materials such as vinyl copolymers and their salts Child, and the like.

  Among these, a polymer compound having a carboxyl group (preferably in the form of a salt) (for example, the above styrene-acrylic acid resin, styrene-maleic acid, styrene-maleic anhydride, vinylnaphthalene-acrylic acid copolymer). Polymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate acrylic acid copolymer), copolymer of monomer having hydrophobic group and monomer having hydrophilic group, and hydrophobic group and hydrophilic group Polymers consisting of monomers with a combination of alkali metal, diethylamine, ammonia, ethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, triethanolamine, diethanolamine, aminomethylpropanol , Morpholine, etc. Preferred salts of. These copolymers preferably have a weight average molecular weight of 3,000 to 300,000, more preferably 10,000 to 250,000.

  It is also preferable to use an aqueous dispersion in which the polymer is dispersed in water in the form of fine particles. These aqueous dispersions can be obtained by appropriately neutralizing a synthetic polymer containing the acid monomer such as acrylic acid or methacrylic acid. The content of the acid monomer is preferably 1% by weight to 15% by weight of the total monomer, and can provide an ink-jet ink that is relatively stable over a relatively long period of time and resistant to aggregation.

  These fine particles may be crosslinked. For example, it is possible to obtain fine particles having a crosslinked structure by using 0.1% by mass to 3% by mass of all monomers as a bifunctional or higher functional crosslinkable monomer. Since the crosslinkable monomer may cause gelation if used in a large amount, it is preferable to use it so that it does not exceed 3% by weight.

  Preferred examples of such an aqueous dispersion include, for example, a synthetic polymer using styrene, (meth) acrylate having 1 to 8 carbon atoms, ethylene glycol di (meth) acrylate, (meth) acrylic acid, and the like as appropriate. An aqueous dispersion obtained by neutralization is mentioned.

  The molecular weight of the resin having a polar group is preferably in the range of 10,000 to 2,000,000, more preferably in the range of 20,000 to 250,000, in terms of weight average molecular weight. When the weight average molecular weight is lower than 20,000, the storage stability of the ink may be deteriorated. If it is higher than 250,000, ink ejection properties are affected, and clogging or the like may easily occur. The glass transition temperature is preferably in the range of −20 ° C. to + 30 ° C. The particle diameter of the fine particles is in the range of 20 nm to 500 nm, more preferably in the range of 100 nm to 300 nm, and an ink having no problem in ejection property can be obtained.

  Here, the particle size can be measured by a centrifugal sedimentation method, a laser diffraction method (light scattering method), an ESA method, a capillary method, an electron microscope method, or the like. Preferable is measurement by Microtrac UPA using a dynamic light scattering method.

(Water or water-soluble organic solvent)
The water used in the water-based ink is preferably pure water or ultrapure water that has undergone a purification process such as ion exchange or distillation. Examples of the water-soluble organic solvent include ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, and methyl isobutyl ketone; methanol, ethanol, 2-propanol, 2-methyl-1-propanol, 1-butanol, 2-methoxy Alcohols such as ethanol; ethers such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane; dimethylformamide, N-methylpyrrolidone, 2-pyrrolidone, LEG-1, glycerol, diethylene glycol, trimethylolpropane And / or the like can be used.

(Surfactant or low surface tension organic solvent)
In order to appropriately adjust the surface tension, a surfactant or a low surface tension organic solvent can be added to the water-based ink. The surfactant is not particularly limited, and examples include various anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, anionic surfactants are included. Agents and nonionic surfactants are preferred.

  Examples of the anionic surfactant include alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfate of higher fatty acid ester, sulfonate of higher fatty acid ester, higher alcohol ether. Sulfate salts and sulfonates of the above, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, etc. Specific examples include dodecylbenzene sulfonate, isopropyl naphthalene sulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenyl sulfonate, dibutylphenylphenol disulfate. , And the like salts.

  Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester , Polyoxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, fatty acid alkylolamide, alkyl alkanolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, Polyethylene glycol polypropylene glycol block copolymer, alkylphenol etoxy Among these, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid Esters, polyoxyethylene sorbitan fatty acid esters, fatty acid alkylol amides, acetylene glycol, oxyethylene adducts of acetylene glycol, polyethylene glycol polypropylene glycol block copolymers, and alkylphenol ethoxylates are preferred.

  Other surfactants include silicone surfactants such as polysiloxane oxyethylene adducts; fluorine surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers. Biosurfactants such as spicrispolic acid, rhamnolipid, lysolecithin and the like can also be used.

  These surfactants can be used alone or in combination of two or more. In consideration of the dissolution stability of the surfactant, the HLB is preferably in the range of 7-20.

  As commercially available fluorosurfactants, Novec FC-4430, FC-4432 (above, manufactured by Sumitomo 3M), Zonyl FSO-100, FSN-100, FS-300, FSO (above, manufactured by DuPont), Ftop EF- 122A, EF-351, 352801, 802 (Gemco), MegaFuck F-470, F-1405, F474, F-444 (DIC), Surflon S-111, S-112, S-113, S121, S131 , S132, S-141, S-145 (manufactured by Asahi Glass), footage series (manufactured by Neos), Fluorad FC series (manufactured by Minnesota Mining and Manufacturing Company), Monflor (Imperial) (Chemical Industry) Kobetto (Licowet) VPF series (manufactured by Farubeberuke Hoechst), and the like.

  Examples of the silicon-based surfactant include KF-351A, KF-642, Olphine PD-501, Olphine PD-502, Olphine PD-570 (manufactured by Shin-Etsu Chemical Co., Ltd.), BYK347, BYK348 (manufactured by BYK Japan).

  The polyoxyethylene alkyl ether activators include BT series (Nikko Chemicals), Nonipol series (Sanyo Kasei), D-, P-series (Takemoto Yushi), EMALEX DAPE series (Nippon Emulsion), Pegnol series (Toho) Chemical industry). An example of the polyethylene glycol alkyl ester system is peganol (Toho Chemical Industries).

  Examples of acetylene glycol surfactants include Olphine E1010, STG, Y (manufactured by Nissin Chemical Co., Ltd.), Surfynol 104, 82, 420, 440, 465, 485, TG (manufactured by Air Products and Chemicals Inc.). Can be mentioned.

  A low surface tension organic solvent can also be used. For example, as glycol ether compounds, diethylene glycol mono (C 1-8 alkyl) ether, triethylene glycol mono (C 1-8 alkyl) ether, propylene glycol mono (C 1-6 alkyl) ether, di Mention may be made of propylene glycol mono (C1-6 alkyl) ethers, which can be used as one or a mixture of two or more.

  Specifically, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-iso-propyl ether, ethylene glycol monobutyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl Ether, diethylene glycol mono-iso-propyl ether, diethylene glycol monobutyl ether, diethylene glycol mono-t-butyl ether, diethylene glycol monopentyl ether, diethylene glycol monohexyl ether, diethylene glycol monoheptyl ether, diethylene glycol monooctyl ether, triethylene glycol Cole monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, triethylene glycol monopentyl ether, triethylene glycol monohexyl ether, triethylene glycol monoheptyl ether, triethylene glycol monooctyl Tityl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol mono-iso-propyl ether, propylene glycol monobutyl ether, propylene glycol mono-t-butyl ether, propylene glycol monopentyl ether, propylene glycol Mono hex Ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol mono-iso-propyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopentyl ether, dipropylene glycol monohexyl An ether etc. can be mentioned.

  Glycol ethers and surfactants can be used to adjust the surface tension of the ink. Specifically, the ink can be appropriately added so that the surface tension of the ink is 15 mN / m to 30 mN / m or less, and the addition amount of the surfactant is preferably in the range of about 0.1 to 10% by mass with respect to the ink composition. More preferably, it is 0.3-2 mass%. The surface tension is more preferably in the range of 16 to 28, and most preferably in the range of 18 to 25.

(Wetting agent)
Furthermore, a wetting agent can be similarly added to the water-based ink for the purpose of preventing the ink from drying. The content of the wetting agent in the ink for the purpose of preventing drying is preferably 3 to 50% by mass. The wetting agent is not particularly limited, but a wetting agent that is miscible with water and can prevent clogging of an inkjet printer head is preferable. For example, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol having a molecular weight of 2000 or less, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, 1,2-butane Diol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-methylpentane-2,4-diol, 1, Diol compounds such as 2-heptanediol, 1,2-nonanediol, 1,2-octanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-nonanediol, 1,2-octanediol 1,4-butanediol, 1,3-butanediol, mesoerythritol, pentaerythritol, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, and nitrogen-containing heterocyclic compounds such as ε-caprolactam. Among them, the inclusion of propylene glycol and 1,3-butyl glycol has safety and excellent effects in ink drying properties and ejection performance.

(Penetration agent)
Further, a penetrant can be added to the water-based ink for the purpose of improving the permeability to a film as a recording medium and adjusting the dot diameter on the recording medium. Examples of the penetrant include lower alcohols such as ethanol and isopropyl alcohol, ethylene oxide adducts of alkyl alcohols such as ethylene glycol hexyl ether and diethylene glycol butyl ether, and propylene oxide adducts of alkyl alcohols such as propylene glycol propyl ether. The penetrant content in the ink is preferably 0.01 to 10% by mass.

  In addition, antiseptics, viscosity modifiers, pH adjusters, chelating agents, plasticizers, antioxidants, ultraviolet absorbers, and the like can be added as necessary.

(Production method)
The method for producing the water-based ink used in the present invention is not limited at all. A coloring material such as the pigment, a resin having the polar group, water or a water-soluble organic solvent, and an additive such as a surfactant as necessary may be charged and dispersed to form a water-based ink. A water-based ink may be prepared by preparing a mill base having a high concentration of coloring material and diluting and appropriately adding additives. In the following, a method for forming the latter mill base and making it a water-based ink will be described.

As a manufacturing method of the mill base,
(1) A method of preparing an aqueous pigment dispersion by adding a coloring material to an aqueous medium containing a pigment dispersant and water and then dispersing the coloring material in the aqueous medium using a stirring / dispersing device.
(2) The coloring material and the pigment dispersant are kneaded using a kneader such as two rolls or a mixer, and the obtained kneaded material is added to an aqueous medium containing water, and the mixture is aqueous using a stirring / dispersing device. A method for preparing a pigment dispersion.
(3) After adding a coloring material to a solution obtained by dissolving a pigment dispersant in an organic solvent having compatibility with water such as methyl ethyl ketone and tetrahydrofuran, the white pigment is organically mixed using a stirring / dispersing device. A method of preparing an aqueous pigment dispersion by dispersing in a solution and then emulsifying by phase inversion using an aqueous medium, and then distilling off the organic solvent.
Etc.

  Examples of the agitation / dispersing device include an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a ball mill, a roll mill, a sand mill, a sand grinder, a dyno mill, a disperse mat, an SC mill, and a nanomizer. May be used alone, or two or more kinds of apparatuses may be used in combination.

  The printing method is preferably ink jet printing, but printing may be performed by other printing methods such as offset printing, letterpress printing, gravure printing, silk screen printing, or a combination of these two or more printing methods. It doesn't matter.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these. In the examples, “part” and “%” are based on mass unless otherwise specified.

[Evaluation of ink coating suitability]
A water-based ink was applied to an A4 size film with a bar coater (No. 6), and the number of repels was visually measured.
○: No repelling.
X: There are one or more repels.

[Evaluation of heat resistance of film]
After printing, the appearance of the film when dried at 90 ° C. for 1 minute was visually evaluated.
○: Almost no defects in appearance such as kinks, wrinkles and film deformation.
Δ: Appearance defects such as slight kinks, wrinkles and film deformation are observed.
X: Appearance defects such as significant kinks, wrinkles, and film deformation are observed.

[Evaluation of printability]
It was visually evaluated whether or not stable ink transfer (printing) was performed on the (A2) surface of the recording medium.
○: Printed satisfactorily with no prints or no printable parts.
×: Printing is faint or there are parts that cannot be printed, and there is a printing defect.

[Evaluation of ink adhesion after printing]
A cellophane tape (manufactured by Nichiban) peel test was conducted and visually evaluated.
○: No peeling.
X: There is peeling.

[Preparation example of water-based ink]
As the water-based ink, a commercially available cyan ink (manufactured by Hured Packard, HP DESIGNJET L25500) was used, and ink coating suitability was evaluated. As a result of measuring the surface tension of the ink at a temperature of 25 ° C. by a platinum plate method using a surface tension meter (manufactured by Kyowa Interface Science: CBVP-A3), it was 18.2 mN / m. Similarly, the result of measuring the viscosity at 25 ° C. using a viscometer (manufactured by Toa DKK: TVE-25L) was 3.22 mPa · s.

  Regarding the adjustment of the printed matter using water-based ink, inkjet printing was performed on the (A2) surface of the recording medium using an inkjet printer “HP DESIGNJET L25500” (manufactured by Hured Packard).

Example 1
As the resin for the resin layer (A1), homopolypropylene [MFR: 10 G / 10 min (230 ° C., 21.18 N), melting point: 163 ° C .; hereinafter referred to as “HOPP”] was used. As the resin for the resin layer (A2), ethylene- (meth) methyl acrylate copolymer (density: 0.940 g / cm ³ , MA content 18%; hereinafter referred to as “MA1”) was used. Each of these resins is supplied to an extruder for a resin layer (A1) (caliber 50 mm) and an extruder for a resin layer (A2) (caliber 50 mm) and melted at 200 to 250 ° C. Co-extruded multilayer film manufacturing apparatus (feed block and T-die temperature: 250 ° C.) having T die / chill roll method and co-melt extrusion are carried out, and the layer structure of the film is (A1) / (A2) A two-layered coextruded multilayer film having a thickness of 96 μm / 24 μm (total 120 μm) was obtained. After the corona discharge treatment was performed on the surface of the (A2) layer of the support so that the wetting tension was 40 mN / m, the printed matter of Example 1 was printed by using the aqueous ink obtained in the preparation example. Produced.

Example 2
An ink-jet printed material was produced in the same manner as in Example 1 except that the thickness of each layer of the layer structure (A1) / (A2) of the film of Example 1 was 56 μm / 14 μm (total 70 μm).

Example 3
An ink jet printed matter was produced in the same manner as in Example 1 except that the thickness of each layer of the layer constitution (A1) / (A2) of the film of Example 1 was 24 μm / 6 μm (total 30 μm).

Example 4
The acid-modified olefin resin of the resin layer (A2) of Example 1 was replaced with an ethylene-methyl acrylate copolymer (MA content 12%, density: 0.933 g / cm ³ ; hereinafter referred to as “MA2”). An ink-jet printed material was produced in the same manner as in Example 1 except that.

Example 5
The acid-modified olefin resin of the resin layer (A2) of Example 1 is an ethylene-methyl acrylate-maleic anhydride copolymer [density: 1.00 g / cm ³ , copolymer content: 15%; hereinafter referred to as “MA3”. An inkjet printed material was produced in the same manner as in Example 1 except that the description was replaced.

Example 6
50% of resin MA1 for resin layer (A2) of Example 1 and propylene-ethylene copolymer [density: 0.900 g / cm ³ , MFR: 7-9 g / 10 min (230 ° C., 21.18 N), Melting point: 150 ° C .; hereinafter referred to as “COPP”] An ink-jet print was prepared in the same manner as in Example 1 except that the composition was replaced with 50%.

Example 7
An ink jet print was produced in the same manner as in Example 1 except that the resin MA1 for the resin layer (A2) of Example 1 was replaced with a blend of 20% and COPP of 80%.

Example 8
The HOPP of the resin layer (A1) of Example 6 is made of high-density polyethylene [density: 0.963 g / cm ³ , MFR: 7 g / 10 min (190 ° C., 21.18 N), melting point 130 ° C .; hereinafter referred to as “HDPE”. An ink-jet printed material was produced in the same manner as in Example 6 except that the description was replaced.

Example 9
HOPP of the resin layer (A1) of Example 6 was changed to medium density polyethylene [density: 0.934 g / cm ³ , MFR: 5.3 g / 10 min (190 ° C., 21.18 N), melting point 119 ° C .; Inkjet printed matter was produced in the same manner as in Example 6 except that the above was replaced.

Example 10
Example 1 except that the acrylic acid-modified resin of Example 1 was replaced with an ethylene- (meth) acrylic acid copolymer [density: 0.940 g / cm ³ , acid modification rate 12%; hereinafter referred to as “MA4”] In the same manner as in Example 1, an inkjet printed material was produced.

Example 11
An ink jet print was produced in the same manner as in Example 1 except that the thickness of each layer of the layer structure (A1) / (A2) of Example 1 was 114 μm / 6 μm (total 120 μm).

Example 12
An ink jet printed matter was produced in the same manner as in Example 1 except that the thickness of each layer of the layer structure (A1) / (A2) of the film of Example 1 was 90 μm / 30 μm (total 120 μm).

Comparative Example 1
An ink jet print was produced in the same manner as in Example 1 except that the acid-modified olefin resin in the resin layer (A2) of Example 1 was replaced with COPP.

Comparative Example 2
An inkjet printed material was produced in the same manner as in Example 1 except that the acid-modified olefin resin in the resin layer (A2) of Example 1 was replaced with HDPE.

  The evaluation results for the printed matter obtained above are shown in Tables 1-2.

  The inkjet printed matter of the present invention can be used for various purposes such as outdoor advertisements (posters, banners, etc.), labels, wallpaper, packaging films, postcards, OHP sheets, jet paper, lottery tickets, forms, and the like.

Claims (10)

On the surface of the layer (A2) of the multilayer film in which the layer (A1) containing the polyolefin resin (A1) as a main component and the layer (A2) containing the acid-modified olefin resin (A2) are laminated,
It comprises at least a colorant, a resin having a polar group, and water or a water-soluble organic solvent, has a surface tension at 25 ° C. in the range of 15 mN / m to 30 mN / m, and a viscosity of 5 mPa · s or less. A method for producing a water-based inkjet printed matter, wherein printing is performed by an inkjet recording method using the water-based ink. The method for producing an aqueous inkjet printed matter according to claim 1, wherein the polyolefin resin (a1) has a melting point of 110 ° C or higher. The method for producing an aqueous inkjet printed matter according to claim 1 or 2, wherein a modification rate in the acid-modified olefin resin (a2) is in a range of 0.5 to 40%. The method for producing an aqueous inkjet printed matter according to any one of claims 1 to 3, wherein the layer (A2) further contains a polyolefin-based resin. The water-based inkjet printed matter according to any one of claims 1 to 4, wherein the acid-modified olefin resin (a2) is contained in 20 parts by mass or more in 100 parts by mass of the resin component forming the layer (A2). Manufacturing method. The method for producing an aqueous inkjet printed matter according to any one of claims 1 to 5, wherein the layer (A1) and the layer (A2) are laminated by a coextrusion lamination method. The method for producing a water-based inkjet printed matter according to claim 1, wherein the water-based ink contains a surfactant or a low surface tension organic solvent. The method for producing an aqueous inkjet printed matter according to claim 1, wherein printing is performed while heating the multilayer film, or the multilayer film after printing is heated. A layer (A1) containing a polyolefin resin (a1) as a main component and a layer (A2) containing an acid-modified olefin resin (a2) are laminated, and the layer (A1) and the layer (A2) The ratio of the layer (A2) to the total thickness of 5 to 40% is a recording medium for water-based inkjet inks. A water-based inkjet printed matter obtained by performing inkjet printing using a water-based ink on the surface (A2) of the recording medium for water-based inkjet ink according to claim 9.